秦岭南北1951-2009年的气温与热量资源变化

根据47 个地面气象站1951-2009 年日气温资料,对秦岭南北近60 年温度带划分指标(包括年平均气温、日平均气温稳定≥ 10 ℃的日数与积温、最冷月与最热月气温、极端最低气温等) 的变化特征进行了分析,结果发现：秦岭南北气候增暖主要出现在20 世纪90 年代初之后,年平均气温、日平均气温≥ 10 ℃的日数和积温的变化趋势基本一致,1951-1993 年在年代波动中略有下降,而1993 年之后则快速上升;但存在着季节和区域差异。在季节上,冷季(1 月) 平均气温与极端最低气温变化趋势一致,1951-1985 年均在波动中略有上升,1985 年之后出现微弱下降;而暖季(7 月) 温度总体变化趋势不明显。在区域上,1993 年之后,秦岭以北、秦岭南坡、汉水流域及巴巫谷地的日平均气温稳定≥ 10 ℃的日数分别较1993 年之前增加了10 天、10 天、8 天和5 天,相应时段的积温分别增加了278 ℃、251 ℃、235 ℃和207 ℃;即20 世纪90 年代初以来,秦岭以北气温与热量资源增加幅度要比秦岭以南稍大一些。

Variation of Air Temperature and Thermal Resources in the Northern and Southern Regions of the Qinling Mountains from 1951 to 2009

On the basis of daily air temperature data from 47 meteorological stations in the northern and southern regions of the Qinling Mountains (QLM) from 1951 to 2009, the variations of several criteria for temperature zones were analyzed including the mean annual temperature, the number of days with steady temperature above 10 ℃ and its accumulated temperature, the minimum temperature, mean temperatures during the coldest and hottest seasons. Our results show that climate warming in both northern and southern QLM was mainly observed after the 1990s, and the trends of mean annual temperature were consistent with the number of days with steady temperature above 10 ℃ and the accumulated temperature. Although these three indices showed a slight decline from 1951 to 1993 and a rapid increase since 1993, some seasonal and regional differences do exist. The average temperature of cold seasons of January exhibited the same changing trends with the minimum temperature, since they both slightly increased from 1951 to 1985 and declined since 1985. Meanwhile, the average temperature of hot seasons of July showed no significant trends. In addition, the increment of some indices showed differences among the northern areas to the QLM, southern slope of QLM, Hanshui River Basin and valleys in Daba and Wushan mountains. Compared with the period before 1993, the number of days with accumulated temperature steadily above 10 ℃ increased by 10, 10, 8 and 5 in the above four regions after 1993, accompanied by increments of related accumulated temperature by 278 ℃, 251 ℃, 235 ℃ and 207 ℃ respectively. Although the increment of thermal resources in the northern region of QLM had larger extent than that in the southern region, their variation trends were consistent and more marked in the cold season. Thus, the Qinling Mountains are still a boundary between the warm temperate zone and sub-tropical zone in China under the background of climate warming since the 1990s.